In the Suwen Cough Book, it is stated that “all five internal organs and six internal organs cause coughing, not only the lungs”. In addition to respiratory diseases, chronic cough is associated with several systemic diseases, such as otorhinolaryngology, digestive system and cardiovascular system diseases. Both Chinese and American cough guidelines state that upper airway cough syndrome (UACS) is one of the most common causes of chronic cough.
With the promotion of cough guidelines, its awareness among physicians has become increasingly popular, and the level of diagnosis and treatment has improved significantly. However, in clinical practice, we find that misdiagnosis and mismanagement of UACS are still very common. In this paper, we analyze the causes of misdiagnosis and mismanagement of UACS from a typical case.
Misdiagnosis case
The patient was a 44-year-old male teacher who came to our hospital with “recurrent cough for 3 years”.
History The patient developed a cough three years ago after a cold, mainly a dry cough with occasional small amounts of white mucous sputum, mostly occurring during the day. The cough was not associated with irritating odors, body position, season or food intake. There was no abdominal distension, acid reflux, belching, nasal congestion, runny nose, postnasal drip influenza, fever, night sweats, hemoptysis, chest pain, wheezing and other symptoms. Since the onset of the disease, he had no weight loss and had been seen at several large general hospitals over the past 3 years, and had received chest X-ray and CT examinations, as well as pulmonary function, bronchial excitation test and induced sputum cytology. He had been diagnosed with bronchitis, chronic pharyngitis and allergic cough. Treatment with antibiotics, glucocorticoids, anti-allergy and cough and sputum relief were ineffective. After taking a detailed history, the attending physician learned that the patient had frontal and facial distention, a history of runny nose as a teenager, and could not rule out upper airway cough syndrome (UACS) due to sinusitis. The patient was then advised to undergo sinus CT, the results of which suggested bilateral inflammation of the frontal and maxillary sinuses.
Examination The pharyngeal mucosa was mildly congested, the tonsils were not enlarged, and the physical examination of the heart, lungs, and abdomen showed no abnormalities.
Diagnosis Upper airway cough syndrome (bilateral inflammation of the frontal and maxillary sinuses).
Treatment The patient was treated with nasal inhalation of hormones, macrolides, mucus promoters and decongestants. 2 weeks later, the patient began to experience significant relief of symptoms. 2 months later, at follow-up, the cough basically disappeared.
Case analysis The primary principle in diagnosing the etiology of chronic cough is to pay attention to history and physical examination, and to narrow the diagnosis through history questioning. UACS was not considered in the early diagnosis of this patient because of the absence of typical upper airway symptoms such as postnasal drip, pharyngeal itching, throat clearing, pharyngeal mucus adhesion sign, lymphatic follicular hyperplasia, and pharyngeal pebble-like sign.
Insufficient knowledge of the etiological components and diagnostic process of chronic cough
The etiologic composition of chronic cough varies between regions. In the European and American populations, UACS, bronchial asthma, and gastroesophageal reflux cough are common etiologies. The common causes of chronic cough in China are, in order of prevalence, cough variant asthma, UACS, eosinophilic bronchitis, and allergic cough.
For patients in primary care hospitals, physicians must consider the sequential order of common etiologies when performing empirical treatment; when conditions are available for a cause-oriented diagnostic process for chronic cough, the possibility of UACS should be considered first if the patient has normal lung function and excitation test and induction sputum findings, and has a history or symptoms related to the upper airway.
Lack of specificity of symptoms in some patients
UACS was once called postnasal drip syndrome (PNDS). PNDS refers to a syndrome in which nasal disease causes secretions to back up into the postnasal and pharyngeal regions or even back up into the vocal cords or trachea, causing a cough as the main manifestation. However, recent studies have found that about one-third of patients with PNDS do not have typical postnasal drip and pharyngeal mucus adhesion signs. In contrast, only a minority of patients with nasal disease in the presence of significant postnasal drip influenza present with cough symptoms.
The American College of Chest Physicians renamed PNDS as UACS in 2006 because it was not clear whether the cough caused by upper airway disease was a direct result of postnasal drip irritation. However, primary care physicians often misdiagnose these patients as having chronic laryngitis.
In particular, it is important not to easily label chronic cough as “chronic laryngitis” or “UACS” in patients with clinical signs and symptoms of laryngitis only, but to carefully rule out other common causes.
Multidisciplinary etiology
UACS is a syndrome that involves multiple underlying diseases of the nose, sinuses, pharynx and larynx (Table). The diagnosis of UACS is somewhat affected by the limited knowledge of otorhinolaryngology disciplines among general internists or respiratory specialists. Therefore, increasing the knowledge of related disciplines and strengthening interdisciplinary collaboration will help reduce misdiagnosis and mismanagement of UACS.
Since the most common underlying diseases of UACS are allergic rhinitis and sinusitis, clinicians should pay attention to them when diagnosing and treating the disease. If other relatively uncommon underlying causes are involved, they should be treated in conjunction with an otolaryngologist.
In addition, the treatment of UACS varies depending on the patient’s underlying disease, with some patients taking longer to treat and even having poorer results with medical therapy alone. Compared to cough variant asthma and chronic cough due to eosinophilic bronchitis, the efficacy of UACS is not judged quickly and easily enough. The definitive diagnosis of UACS is somewhat influenced by the fact that the patient’s response to treatment is necessary to clarify the etiology of chronic cough.
For example, for patients with chronic non-allergic rhinitis, topical nasal glucocorticoids are recommended for no shorter than 3 months. For chronic rhinosinusitis, antibiotic treatment for 4-12 weeks and routine nasal glucocorticoid use for no shorter than 3 months is recommended, combined with low-dose macrolides, decongestants, mucus promoters, and saline rinses of the nasal cavity. If medical treatment is not effective, surgical intervention is recommended as appropriate.
Therefore, the correct diagnosis of UACS must be based on a comprehensive evaluation that takes into account the patient’s symptoms, physical and ancillary findings, and the patient’s response to treatment.